The present invention relates generally to a seat suspension protection device and, more particularly, to a mechanical ride zone protection device for a pneumatic seat suspension having a swivel arm which pivotally moves with the seat and includes a cam which alternatively allows and prevents vertical seat adjustment.
Many vehicle seats today are vertically adjustable using an air suspension. In such suspension systems, compressed air allows the seat to be raised or lowered vertically when actuated. These seat suspension systems generally include scissors linkage or parallelogram-type mechanical connections between the seat and the vehicle frame as generally described in U.S. Pat. Nos. 3,826,457; 3,339,906; 4,125,242; and 5,125,631; all incorporated herein by reference. As such, the seats are vertically adjustable only within a defined range, called the ride zone. The air suspension system allows the seat to be lowered to its lowest vertical position and raised to its maximum vertical height.
A problem with such systems occurs when the seat occupant raises the seat to its maximum height or lowers the seat to its lowest point. At such extreme positions, the seat may provide little suspension and comfort for the seat occupant. As such, the seat is uncomfortable and may cause back ailments because the seat suspension is not working to provide suitable shock absorption.
One way to prevent such problems from occurring is to prevent the seat from being positioned to its lowest and highest positions, i.e. to prevent or regulate the air suspension system from completely charging or discharging the air spring. The present invention provides for a mechanical apparatus which prevents the air compressor from working to charge the air spring to adjust the seat to its maximum height or completely discharge the air spring to "bottom out" the suspension.
The present invention provides a mechanical apparatus which ensures that the seat remains within the intended ride zone, i.e. that the air suspension system operates to raise or lower the seat to maximum or minimum height levels that insure adequate shock absorption and comfort during normal operating conditions.